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Neogastropoda
Neogastropoda is an order of aquatic snails, both freshwater and marine gastropod molluscs. Description The available fossil record of Neogastropoda is relatively complete, and supports a widely accepted evolutionary scenario of an Early Cretaceous origin of the group followed by two rapid diversification rounds in the late Cretaceous and the Paleocene. These sea snails have only one auricle, one kidney and one monopectinate gill, i.e. the gill filaments develop on only one side of the central axis. The shell has a well-developed siphonal canal. The elongated trunk-like siphon is an extensible tube, formed from a fold in the mantle. It is used to suck water into the mantle cavity. At the base of the siphon is the bipectinate (branching from a central axis) osphradium, a sensory receptacle and olfactory organ, that is more developed than the one in the Mesogastropoda. They achieved important morphological changes including e.g., the elongation of the siphonal canal, a shift ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muricidae
Muricidae is a large and varied taxonomic family of small to large predatory sea snails, marine gastropod mollusks, commonly known as murex snails or rock snails. With over 1,700 living species, the Muricidae represent almost 10% of the Neogastropoda. Additionally, 1,200 fossil species have been recognized.Houart, Roland. (2018). "Historique et classification des espèces actuelles de Muricidae (Neogastropoda, Muricoidea)." ''Novapex'' 19:37–66 Numerous subfamilies are recognized, although experts disagree about the subfamily divisions and the definitions of the genera. Many muricids have unusual shells which are considered attractive by shell collectors and by interior designers. Shell description Muricid shells are variably shaped, generally with a raised spire and strong sculpture with spiral ridges and often axial varices (typically three or more varices on each whorl), also frequently bearing spines, tubercles, or blade-like processes. Periostracum is absent in thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clea (gastropod)
''Clea'' is a genus of freshwater snails with opercula, aquatic gastropod mollusks in the subfamily Anentominae of the family Nassariidae, a family, almost all of the rest of which are marine. Name The members of this genus are known as assassin snails for their habit of eating other snails. They bury themselves and ambush their prey. Taxonomy This genus was originally described within the family Buccinidae. It was moved to family Nassariidae in 2016.Galindo, L. A., Puillandre, N., Utge, J., Lozouet, P., & Bouchet, P. (2016). "The phylogeny and systematics of the Nassariidae revisited (Gastropoda, Buccinoidea)". ''Molecular Phylogenetics and Evolution'' 99: 337-353. It was classified in the newly established subfamily Anentominae within Nassariidae in 2017.Strong, E. E., Galindo, L. A., & Kantor, Y. I. (2017). "Quid est ''Clea helena''? Evidence for a previously unrecognized radiation of assassin snails (Gastropoda: Buccinoidea: Nassariidae)". ''PeerJ'' 5: e3638. . S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tulip Shell
Tulip snail or tulip shell is the common name for eight species of large, predatory, subtropical and tropical sea snails from the Western Atlantic. These species are in the genus ''Fasciolaria''. They are marine gastropod mollusks in the family Fasciolariidae, the spindle shells, tulip shells and their allies. The word "tulip" describes the overall shape of the shells of these species, which is like that of a closed tulip flower. Description The shell is fusiform. The spire is acuminated. The aperture is oval, elongated, as long as the spire. The siphonal canal is straight. The columella is smooth, with a few oblique plaits at the fore part. The outer lip is internally crenate. Species According to the World Register of Marine Species (WoRMS), and the Digital Atlas of Ancient Life for the Neogene of the Southeastern United States, the following species with a valid name are included within the genus ''Fasciolaria'' : * † ''Fasciolaria apicina'' Dall, 1890 *'' Fasciolaria b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cone Snail
Cone snails, or cones, are highly venomous sea snails that constitute the family Conidae. ''Conidae'' is a taxonomic family (previously subfamily) of predatory marine gastropod molluscs in the superfamily Conoidea. The 2014 classification of the superfamily Conoidea groups only cone snails in the family Conidae. Some previous classifications grouped the cone snails in a subfamily, Coninae. As of March 2015 Conidae contained over 800 recognized species, varying widely in size from lengths of 1.3 cm to 21.6 cm. Working in 18th-century Europe, Carl Linnaeus knew of only 30 species that are still considered valid. Fossils of cone snails have been found from the Eocene to the Holocene epochs. Cone snail species have shells that are roughly conical in shape. Many species have colorful patterning on the shell surface. Cone snails are almost exclusively tropical in distribution. All cone snails are venomous and capable of stinging. Cone snails use a modified radula tooth and a venom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radula
The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the mollusks, and is found in every class of mollusk except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth. Within the gastropods, the radula is used in feeding by both herbivorous and carnivorous snails and slugs. The arrangement of teeth ( denticles) on the radular ribbon varies considerably from one group to another. In most of the more ancient lineages of gastropods, the radula is used to graze, by scraping diatoms and other microscopic algae off rock surfaces and other substrates. Predatory marine snails such as the Naticidae use the radula plus an acidic secretion to bore through the shell of other mollusks. Other predatory marine snails, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siphonal Canal
The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. Siphonal canals allow for active transport of water to sensory organs inside the shell. Organisms without siphonal canals in their shells rely on passive or diffuse transport or water into their shell. Those with siphonal canals have a direct inhalant stream of water that interacts with sensory organs to detect concentration and direction of a stimulus, such as food or mates. In certain groups of carnivorous snails, where the siphon is particularly long, the structure of the shell has been modified in order to house and protect the soft structure of the siphon. Thus the siphonal canal is a semi-tubular extension of the aperture of the shell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 Megaannum#SI prefix multipliers, Ma to 100.5 Ma. Geology Proposals for the exact age of the Barremian–Aptian boundary ranged from 126 to 117 Ma until recently (as of 2019), but based on drillholes in Svalbard the defining Anoxic event#Cretaceous, early Aptian Oceanic Anoxic Event 1a (OAE1a) was dated to 123.1±0.3 Ma, limiting the possible range for the boundary to c. 122–121 Ma. There is a possible link between this anoxic event and a series of Early Cretaceous large igneous provinces (LIP). The Ontong Java Plateau, Ontong Java-Manihiki Plateau, Manihiki-Hikurangi Plateau, Hikurangi large igneous province, emplaced in the South Pacific at c. 120 Ma, is by far the largest LIP in Earth's history. The Onto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whelk
Whelks are any of several carnivorous sea snail species with a swirling, tapered shell. Many are eaten by humans, such as the common whelk of the North Atlantic. Most whelks belong to the family Buccinidae and are known as "true whelks." Others, such as the dog whelk, belong to several sea snail families that are not closely related. True whelks (family Buccinidae) are carnivorous, and feed on annelids, crustaceans, mussels and other molluscs, drilling holes through shells to gain access to the soft tissues. Whelks use chemoreceptors to locate their prey. Many have historically been used, or are still used, by humans and other animals as food. In a reference serving of whelk, there are of food energy, 24 g of protein, 0.34 g of fat, and 8 g of carbohydrates. Dog whelk, a predatory species, was used in antiquity to make a rich red dye that improves in color as it ages. Usage The common name "whelk" is also spelled ''welk'' or even ''wilk''. The species, g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conch
Conch ( , , ) is a common name of a number of different medium-to-large-sized sea snails. Conch shells typically have a high Spire (mollusc), spire and a noticeable siphonal canal (in other words, the shell comes to a noticeable point on both ends). Conchs that are sometimes referred to as "true conchs" are Marine (ocean), marine gastropods in the family (biology), family Strombidae, specifically in the genus ''Strombus'' and other closely related genera. For example, ''Aliger gigas'', the queen conch, is a true conch. True conchs are identified by their long spire. Many other species are also often called "conch", but are not at all closely related to the family Strombidae, including ''Melongena'' species (family Melongenidae) and the horse conch ''Triplofusus papillosus'' (family Fasciolariidae). Species commonly referred to as conches also include the sacred chank or ''shankha'' shell (''Turbinella pyrum'') and other ''Turbinella'' species in the family Turbinellidae. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dioecious
Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is biparental reproduction. Dioecy has costs, since only the female part of the population directly produces offspring. It is one method for excluding self-fertilization and promoting allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population. Plants have several other methods of preventing self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility. In zoology In zoology, dioecy means that an animal is either male or female, in which case the synonym gonochory is more often used. Most animal species are gonochoric, almost all vertebrate species are gonochoric, and all bird and mammal species are gonochoric. Dioecy may also describe colonies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denticle (tooth Feature)
Denticles, also called serrations, are small bumps on a tooth that serve to give the tooth a serrated edge. In paleontology, denticle characteristics such as size and density (denticles per unit distance) are used to describe and classify fossilized teeth, especially those of dinosaurs. Denticles are also present on the teeth of varanoid lizards, sharks, and mammals. The term is also used to describe the analogous radular teeth of mollusks. Archived aPDF File:Dromaeosauridae tooth.TIF, Dromaeosauridae tooth with small denticles along the cutting edge. Scale bars are 1 mm. File:Ankylosaurus tooth.jpg, '' Ankylosaurus'' tooth with large denticles. File:Dentary teeth of Segnosaurus.png, ''Segnosaurus ''Segnosaurus'' is a genus of therizinosaurid dinosaur that lived in what is now southeastern Mongolia during the Late Cretaceous, about 102–86 million years ago. Multiple incomplete but well-preserved specimens were discovered in the Go ...'' dentition featuring a tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
